I wanted to calculate my Dragon Blood's ABV and Residual Sugar %.

I've seen a couple formulas using the initial SG and final SG to calculate the ABV. In my case, the Initial SG was 1.077 and the final (before back sweetening) was 0.991. The formulas use anywhere from 131 to 135 times the difference between initial and final SG. If I use 132 x (1.077-0.991) = 11.35% ABV.

I found the Quick Reference Guide to Estimating a Wines ABV and Residual Sugar in 3 Easy Steps. According to the very scientific research and calculations on website:

http://www.rochesterwinemakers.org/w...and-res-sugar/ there is a direct correlation between the final SG and ABV to the residual sugar %.

Using Rochester Winemakers' 3-step method for my DB, the residual sugar/extract (various non-sugar compounds in wine like tannin, acids, glycerol, & pigments) is about 1.8%. Step 3 subtracted the extract component that has contributed to the final RS from the calculated combined extract/RS: 1.8% - 2.2% for white grapes/other fruit = DRY (-.04%). I guess you can't have drier than dry of 0% - maybe we should have a dry, extra dry, etc.!

With my Dragon Blood, I back sweetened my 6+ gallons (volume not known exactly) with 6 cups of sugar to get the SG after back-sweetening to 1.012. How do I account for the additional sugar being added to calculate the true residual sugar?

The Rochester Winemakers Website states "For accurate results, use an SG taken before sweetening as your final SG. Of course you’ll then have to update the residual sugar amount with the new sugar." I'm struggling with how to add my DRY or 0% residual sugar with the 6 cups of added sugar (back-sweetened) to get the final RS%. I don't have the weights of the 6+ gallons of pre-sweetened dry DB to take a % by weight of 6 cups of raw sugar @ 250 g = 1500 g / x grams of 6+ gallons of DB wine.

Any suggestions to calculate the RS?